1. Field of the Invention
The present invention relates to a method and apparatus for providing a workpiece with an identification mark, a method and apparatus for identifying a workpiece, and a sheet metal machining apparatus having a workpiece identifying apparatus.
2. Prior Art
Conventionally, as means for providing workpieces with identification marks, there has been known means for etching characters or numerals on workpieces by means of a punch press, attaching bar codes thereto, or by performing laser marking by means of laser beam machining.
However, in such conventional means for etching of workpieces, providing bar codes or carrying out laser marking, the size of apparatus inevitably become large. Further, when etchings, bar codes or laser marks on workpieces made of sheet metals were read by an identification apparatus, it was difficult to clearly confirm the results of reading if the workpieces or products were dirty or damaged because of little difference in light and darkness between their original colors and the codes. Consequently, it was rather difficult to manage the workpieces or the products.